Harpactea sadistica
Encyclopedia
Harpactea sadistica is a species
of dysderine
spider
, found only in Israel
. It was first described in 2008.
is 2.3 mm long in the holotype
specimen
. The tip of the embolus
of the male resembles the tip of a hypodermic needle
, and the vulva
of the female is atrophied
.
plantations, and in steppe habitats where Asphodelus
is predominant.
Chelicerata
– found to use traumatic insemination
. The males have specialized genital structures at the pedipalp
s that are adapted to grip the female and inject the sperm
, using a structure resembling a hypodermic needle
. After positioning himself, the male pierces the female on both sides and injects the sperm directly into the ovaries
, resulting in about eight holes in two rows. Consistent with the modified mating behavior, the spermatheca
e of the female, which normally store received sperm, are weakly developed in this species.
Whereas in other spiders the eggs are fertilized only when laid, in this special case fertilization takes place at the moment of insemination, and develop as embryos before being laid.
This behavior seems to have evolved in order to ensure that the mating male is also the one providing the sperm for the progeny. Spermathecae fertilise the eggs with the sperm of the last mating male. With the adaption of traumatic insemination, the male ensures that his sperm will be used, circumventing this mechanism.
Like many other spider species, H. sadistica has elaborate mating rituals preceding the insemination, involving tapping the female, subduing her and wrapping himself around her in order to position himself prior to insemination.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of dysderine
Dysderidae
The family Dysderidae are araneomorph spiders found primarily in Eurasia, although extending into North Africa, with very few species occurring in South America, and one introduced into many regions of the world.Dysderids have six eyes, and are haplogyne, i.e...
spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
, found only in Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
. It was first described in 2008.
Description
Both sexes have the same body characteristics. The length of the pale yellow-brown, smooth carapace ranges from 1.1 to 1.7 mm. The legs are pale yellow, with the first two pairs darker than the other two. The cylindrical, whitish opisthosomaOpisthosoma
The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma . It is a distinctive feature of the subphylum Chelicerata...
is 2.3 mm long in the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
specimen
Specimen
A specimen is a portion/quantity of material for use in testing, examination, or study.BiologyA laboratory specimen is an individual animal, part of an animal, a plant, part of a plant, or a microorganism, used as a representative to study the properties of the whole population of that species or...
. The tip of the embolus
Embolus
An embolus is any detached, itinerant intravascular mass carried by circulation, which is capable of clogging arterial capillary beds at a site distant from its point of origin.By contrast there are non-traveling blockages that develop locally from vascular trauma or...
of the male resembles the tip of a hypodermic needle
Hypodermic needle
A hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it...
, and the vulva
Vulva
The vulva consists of the external genital organs of the female mammal. This article deals with the vulva of the human being, although the structures are similar for other mammals....
of the female is atrophied
Atrophy
Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...
.
Ecology
H. sadistica probably exhibits an annual lifecycle. Eggs are laid from March to April. The species is found in woodlands dominated by Quercus calliprinos and pinePine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
plantations, and in steppe habitats where Asphodelus
Asphodelus
Asphodelus is a genus of mainly perennial plants native to western, central and southern Europe, but now spread worldwide. Asphodels are popular garden plants, which grow in well-drained soils with abundant natural light...
is predominant.
Traumatic insemination
H. sadistica is the first spider species – and the first member of the entire subphylumSubphylum
In life, a subphylum is a taxonomic rank intermediate between phylum and superclass. The rank of subdivision in plants and fungi is equivalent to subphylum.Not all phyla are divided into subphyla...
Chelicerata
Chelicerata
The subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda, and includes horseshoe crabs, scorpions, spiders and mites...
– found to use traumatic insemination
Traumatic insemination
Traumatic insemination, also known as hypodermic insemination, is the mating practice in some species of invertebrates in which the male pierces the female's abdomen with his penis and injects his sperm through the wound into her abdominal cavity . The sperm diffuse through the female's hemolymph,...
. The males have specialized genital structures at the pedipalp
Pedipalp
Pedipalps , are the second pair of appendages of the prosoma in the subphylum Chelicerata. They are traditionally thought to be homologous with mandibles in Crustacea and insects, although more recent studies Pedipalps (commonly shortened to palps or palpi), are the second pair of appendages of the...
s that are adapted to grip the female and inject the sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
, using a structure resembling a hypodermic needle
Hypodermic needle
A hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it...
. After positioning himself, the male pierces the female on both sides and injects the sperm directly into the ovaries
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
, resulting in about eight holes in two rows. Consistent with the modified mating behavior, the spermatheca
Spermatheca
The spermatheca , also called receptaculum seminis , is an organ of the female reproductive tract in insects, some molluscs, oligochaeta worms and certain other invertebrates and vertebrates...
e of the female, which normally store received sperm, are weakly developed in this species.
Whereas in other spiders the eggs are fertilized only when laid, in this special case fertilization takes place at the moment of insemination, and develop as embryos before being laid.
This behavior seems to have evolved in order to ensure that the mating male is also the one providing the sperm for the progeny. Spermathecae fertilise the eggs with the sperm of the last mating male. With the adaption of traumatic insemination, the male ensures that his sperm will be used, circumventing this mechanism.
Like many other spider species, H. sadistica has elaborate mating rituals preceding the insemination, involving tapping the female, subduing her and wrapping himself around her in order to position himself prior to insemination.
Name
The species name refers to the seemingly sadistic habit of severing the body cavity of the female.External links
- Royal Society: Mating of H. sadistica: Videos